Bag for preserving foodstuffs and method of making



April-29. 1941.

H. M. J. T. DE YFoixk BAG FOR PRESEBVING FOODSTUFFS ANDHETHOD'QF MAKING Filed June 7, 1938 2 Sheets-Sheet 1 Henri M. J. de Ppix April 29, 1941. H. M. J. T.` DE Polx 2,240,245' BAG FOR PRESERVING FOODSTFFS AND METHOD 0F MAKING l Filed June 7. 1938 2 Sheets-Sheet 2 :Elin/EMM:

l Henri M,J.T. de Paix f mne,

'UNITED STATES PATENT OFFICE' BAG FOR PRESERVING FOODSTUFFS AND METHOD OF MAKING Henri Marie Joseph Tyrel de Poix, Rueil, France,

assigner to Dewey and Almy Chemical Company, Cambridge, Mass., a corporation of Massyachusetts Application June 7, 193,8, Serial No. 212,359 In France June 22, 1937 i Claims. (Cl. 18.-475) This invention relates to impervious, flexible. containers which may be used in the preservation of foodstuffs and more particularly may be used in connection with the storage, ageing and freezing of such products.

Although the containers of this invention are suitable for use in the preservation of any foodstuffs that may be preserved by refrigeration or freezing, they are particularly suitable for use in the preservation of meats, and, consequently. for convenience in description, I shall describe it as applied to the preservation of beef quarters and carcasses of smaller animals.

.It has been proposed to enclose foodstuffs in .flexible containers, for example, in vulcanized rub er sacks or bags of rubber hydroalides, and afte evacuating the bag, sealing it in such a manner that no air gains entrance. The meat thereafter may be chilled according to conventional practice or frozen, and, in this instance, very quick freezing may be brought about because the covered carcass may be directly immersed in the cold brine or sprayed or hosed down with the refrigerant. Since itis intended to store thc^ foodstuffs in the envelopes for lons periods of time, suitable materials must be permanent and have no ultimate effect on taste or odor.

The containers so far proposed, however, possess very serious drawbacks. If an ordinary rubber sack is used, the vulcanizing agents contaminate the food with oensive tastes and odors,

r but the most serious defect associated with the use of rubber bags lies in the resilience of vulvelopes that reuse is not necessary;

'20 shrunken condition,

a out the necessity of removing the bag and which canizedrubber at low temperatures for, since the as they cover the meat are always distended somewhere, a puncture or aV tear causes the rubber to pull away from the immediate vicinity of the tear and sometimes to split for such a distance that the covering is useless. To avoid this defect, the bags have been made from heavy material which causes them to be prohibitively, expensive. Aside from expense, the production oflsuch a large, heavyrubber envelope, presents a serious manufacturing problem in itself.

Bags of other materials which have been proposed are faulty either because they require a subsequent heat treatment at temperatures which are harmful to foods or because of their high cost of manufacture or because the material itself is sc brittle that it is impossible to handle the carcass es frequently as necessary without the probability that he wrapping will be torn and as 'a result, although the advantages of the hermetic wrapping of vmeats for freezing, storing or ageing has been well understood and its effect on the prevention of losses by evaporation and trimming and the retention of juices which it secures is well known, impervious sacks still are not used for the commercial preservation and storage of meat.

It is an object of this invention to produce thin, light and such relatively inexpensiveento produce impervious envelopes which may be sealed in a dependable manner after evacuating or expelling the air; which possess the distinct advantage that they are dead and inelastic at chilling or refrigeration temperatures; that will not pull away and expose any large area of .beef after puncture; that may be shrunk down onto the beef by a simple method to cause the covering to cling to the beef almost as if it were the skin of the animal; and to produce covers which, in their are transparent and relativewrinkles and folds; which permit ly free from the meat to be determined with-` the condition of present an attractive, salable, commercial packagee I have discovered that characteristics of unvulcanized rubber adapt it to the preservation of meats to a wholly unexpected degree. I may now preserve meat and other foodstuffs in extremely thin and, hence. cheap envelopes, and I nd it no longer necessary to provide heavy and expensive coverings since the re-use of the envelope is no longer an eccnomic necessity.

I proceed in the manufacture of such containv ers in the following manner: v

A flattened form, which, if desired, may be shaped into rough conformity with the carcass to be protected, is dipped in a solution of rubber. Preferably, however, stronger coating can be built up quickly on the dipping form, I prefer to dip the form in an aqueous dispersion of natural or artificial rubber, for example, concentrated latex. Aside from the necessary bactericides and latex preservatives, the latex 'need not be further compounded, but dyes and pigments may be added to designate grades or trade-mark articles. The deposit of rubber upon the any of the well known dipping procedures and, after a liquid coating of sufficient thickness has been deposited, the form is withdrawn from the tank of dispersion. Thereafter, the coating of latex is allowed to dry thoroughly. This may be accomplished wholly upon the dipping form itself,

the peculiar physical because a much thicker andv form may be brought about by I although, in order to release the dipping forms as quickly as possible and return them to the dipping machine, I prefer to transfer the partially dried rubber coating to a secondary drying form and to maintain the coating on this form until the water has been evaporated.

The bags are then removed from the drying form and maybe dusted with any suitable nontoxic anti-sticking compound. Since food products are involved. I prefer to use starch as the dusting composition. Bags in this condition may be furnished to the food packer or he may tlnd it preferable to buy the bags in a distended state.

To distend the envelope it is merely necessary to gather the open end of the bag about an iniiating nozzle and blow in compressed air until the rubber envelope has been enlarged to such a size that the carcass may easily be placed therein. In this case, the envelope, except for the neck portion, which was held against the nozzle, will be iniiated to a fairly uniform degree. I1 projections have been formed on the envelope so that pockets are formed to enclose the legs or neck of the animal, the rubber in these projections will not be dlstended to so great a degree and will be thicker and stronger. Therefore, the rubber in the neck portion of the envelope and in the leg pockets is more able to stand the strain of the ligatures which are used for closing the bag and for tying around the legs to hang up the carcass.

Uncured rubber in an expanded or extended condition is physically unstable to a rise in temperature. At room temperature it will contract toward its original size very slowly or not at all. but, if the temperature be raised approximately to 140 F.. it springs back to about 125% of its original size almost instantaneously.

Consequently, if the bags are to be shipped through areas where they may besubjected to high temperatures, it is preferable to supply the food packer with unexpanded bags. If the bags will not be subjected to elevated temperatures in shipment, they may be expanded at the point of their manufacture. At the rood packing plant, after the animal is slaughtered and properly cleaned and prepared, the carcass is placed in one of my expanded rubber envelopes. I1' the envelope has been provided with pockets, the legs o! the beef quarter, mutton or pork are tted into the pockets and then the open end of the bag, i. e. the neck portion oi the envelope, is twisted and securely tied to form an air` tight seal. A vacuum line is attached to a small tube formed on the envelope, and the air which may be trapped between the carcass and the bag is sucked out. At this moment, the bag, which very loosely enfolds the carcass, is pushed against it by the outside atmospheric pressure, 'forming a great` number oi wrinkles and folds. Alternatively, instead of lexhausting the air by vacuum, it may be pressed out from between the carcass and the bag by means of external pressure.

I then heat the wrapped carcass very lbriefly 6 in order to cause the restoringforces in the rubber bag to become active and to cause the folds and wrinkles to disappear. This may be done by dipping the carcass for no more than one or two seconds into water heated to a temperature oi' about 140 F. or the carcass may be pushed through a hot room on its Way to the cooler. Only this momentary heating` is necessary to shrink the coating down against the carcass so tightly that it appears almost as a 7'5 of mold and transparent skin and hardly any spot is left on complicated cuts where the envelope is not in 'close contact with the meat.

The invention may be more readily under- 5 stood by reference to the drawings. Fig. 1 illustrates a form lll, suitable for making an envelope designed to enclose 'a mutton. It comprises a V-shaped web portion Ii bearing two rounded marginal ilanges I2 and It. Il' desired, a small projecting pin it may be attached to the web so that a small tube is formed on the envelope which is used for evacuating the air. Although it ls not necessary, since a plain bagshaped envelope draws down tightly against meats of any shape, I prefer to cut away a portion oi' the web as shown in the ligure so that the flanges I 2 and i3 together with the remaining portions I5 and Il of the web may form pockets in the envelope which ultimately will receive the hind legs of the animal. The forelegs oi' the carcass are bent down against the iblxeast and no pockets need be made to receive The V-shape, better illustrated in Fig. 2, (a section on the line 2, 2 qt Fig. l), ls given to the dipping form merely to conserve space in the tank. The over-ali size o! the dipping form is a. matter of choice. l1 a suiiiciently'thick coat forms which are reduced from l to M; or the size of the animals are found to be satisfactory.

Another form. Il. suitable for making an envelope tor enclosing a quarter of beef is shown in Fig. 3. In this case, a web I8 of G section (Fig. 4) is provided with rounded marginal Iianges I9 and 2|. The small pin 22 is attached to the web at any convenient location to form the evacuating connecting tube. Parts o! the marginal ange 2l and a portion o! the web Il have been cut away so that the remaining portion of the web together with the marginal ange Il will form the leg pocket ot the envelope.

Fig. 5 illustrates the appearance of the envelope 24 as the inflation proceeds. The open end of the envelope 24 is gathered about the inflation nozzle 25 by a rubber band 26. Air is admitted through the pipe 21 and controlled by a valve (not shown). The body portion 28 of the envelope is shown distended to a material deenough to allow it to eniold the whole carcass easily and loosely. Fig. 6 illustrates 32 has now been closed by the string or tape wrapping 33 and hanging loops 34, 34 have been tied about the leg pockets 29 and 3|.

After the envelope has been shrunk into contact with the meat by heating, the meat may merely go to a chill room and be chilled according to conventional practice, but, in all cases from my invention, the the meat until it must be out up for sale by the retail butcher.

The bags may also be used solely for the tenprevents allgrowth spoilagc 'which always ac dering of meat. Their use surface of the meat will be deleteriously affected.

If the meats are frozen, the temperature falls below the so-called freezing temperature of rubber. Then, a dead, inelastic smh is formed which, although scarcely more than .002" or .003" thick, resists scraping and abrasion to an astonishing degree. I It'will not pull away from any puncture or tear and, in effect, the carcass is protected by an inelastic,liquidimpervious.

air-tight envelope in intimate contact with the carcass throughout its whole extent.

I nd it best to retain the envelope on frozen meat at least until all thawing is complete. `The meat may be thawed by hosing the covered carcass with temperate water or it may be hung v in a room atnormal temperatures. Although the bag itself, as soon as it comes to normal temperature, may be stripped away from the meat without diiiiculty, it is much better to leave the bag on the meat until all of the meat has thoroughly thawed. This prevents not only possible contamination of the meat by the thawing water, but also prevents "drip to such a degree that frozen beef thawed in the envelopes closely approaches the quality of chilled beef.

#Although I have described my invention as applied to meat carcasses, it'is obvious that it may be applied in an equally successful manner tothe preservation of poultry, ilsh. and other foodstuffs, and that, Ain the case of these smaller products, it is not necessary to package the individual pieces separately. In the latter case.

vthe envelope can be inserted in a box with its open end turned vdown over the margin of the box. The produce may then be packed in the .envelope as closely as possible and the open end closed and secured with a string or tape wrapping. Thereafter, the bulk package may be placed either in chilling rooms or under a stream or spray of refrigerating liquid.

The ease oi manufacture, low cost, the ease of application. and the surety of protection which my new envelopes give, now makes it possible to in a spray of brine or refrigerant and shrinkage and desiccation may be avoided throughout the whole period of their subsequent storage. The contractability of the envelope and the fact that unvuicanized rubber the properties made use of are found to some degree in rubber iilms made from partially pre-vulcanized latex and illms subjected to low degrees lof vulcanization such as are not now commercially used as vulcanized rubber. Such vrubbers are included in the term unvulcanized `rubber."

What I claim is:

1. The process of producing envelopes suitable for protecting meat and other foodstuis during cold-storage which includes forming an unvulcanized rubber envelope having much smaller dimensions than the foodstui to be protected and then distending the unvulcanized envelope to such a degree that the envelope is rendered physically unstable to a rise intemperature.

2. 'I'he process of producing envelopes suitable for protecting meat and other foodstuffs during cold storage which includes depositing a coating of unvulcaiiized rubber upon a former to form an envelope having leg and neck portions, dry- 'ing the coating, distending the body portion of said unvulcani'zed coating to a greater degree than the neck and leg portions, thereby producing an envelope having physical instability to a rise in temperature and possessing thickened neck and leg portions.

3. An envelope suitable for enclosing meat and other foodstuffs consisting of a exible membrane comprising unvulcanized rubber stretched to between 100% and'600% elongation enclose beef and all foodstuffs in enevolpes in f such a mannerv that they may beY frozen directly it pulls down into tight contact with the meat forms a package through which the meat may bey inspected without the necessity i'or removing the envelope. This last is vparticularly important where the sale of the whole package is made to the ultimate consumer, as in the caseof small cuts of beef or poultry. Though the foregoing describes the use 0f andcapable of shrinking to a material degree when heated.

4. As a completed article of manufacture a iiexible bag or container formed essentially of unvulcanized, rubber, said bag being suitable for enclosing meat and other foodstuffs during refrigeration and being capable when stretched of remaining substantially distended at or below normal room temperature and of shrinking materially when heated.

`5. As a completed article of manufacture a iiexible bag orv container formed essentiallyoi unvulcanized rubber of greater thickness than required in the nal product and having a nontoxic anti-sticking compound on its surface, said bag being suitable for enclosing meat and other foodstuffs during refrigeration and vbeing capable when stretchedof remaining substantially distended at or below normal room temperature and of shrinking Vmaterially when heated.

V6. A bag or container suitable for enclosing meat and other foodstuffs formed essentially of unvulcanized rubber, said rubber being in stretched condition and capable of shrinking materially when heated.

7.` The process of producing envelopes suitable for protecting meat and other foodstuffs during' f cold storage which includes forming an unvul-l canized rubber envelope having a neck portion and a body portion and then distending the body portion of said unvulcanized envelope toI a greater f degree than the neck portion, the body portion-- being distended to such a degree that it will be rendered physically unstable to a rise in temperature whereby an envelope is produced having a neck portion thicker than the body portion.

HENRI MARIE JOSEPH Trani. wrom. 

